Nino3.4 plume amplitude correction


As of Aug 2015, the NMME real time Nino3.4 plume has been corrected for systematic bias in the amplitude. (Correcting for mean error continues unchanged.) The model forecast anomalies have been divided by a correction factor, equal to the ratio of the models' hindcast standard deviation to the standard deviation of the IOSST observed SST (1982-2010). The correction factor is calculated for each model, start month and lead and feeds into the multi-model ensemble. For most but not all models this procedure means a reduction in amplitude of all members, and also the ensemble mean.